Arch Orthop Trauma Surg. 2026 Jul 10;146(1):254. doi: 10.1007/s00402-026-06403-3.
ABSTRACT
INTRODUCTION: To date, few studies have directly compared matched cohorts of patients with severe varus deformity undergoing UKA versus TKA. The current study seeks to address this gap. The hypothesis was that, in patients with deformity of > 15°, postoperative PROMs following UKA would be inferior to those achieved with TKA.
METHODS: Records of patients operated for UKA and TKA from January 2016 to December 2021 were evaluated, and the data for patients with deformity of ≥ 15° were selected. The UKA patients were then matched for age and gender with TKA patients. 52 matched pairs of patients were obtained. The HKA, mLDFA, MPTA were measured. OKS, SF12, and FJS were collected. The magnitude of change in the mLDFA and MPTA was assessed using the Estimated Marginal Means.
RESULTS: The mean follow-up times for UKA and TKA were 3.7 years and 5.5 years, respectively. The mean deformity correction (ΔHKA) was significantly greater in TKA (16.3° ± 4.5°) than UKA (10.6° ± 3.1°) (p < 0.001), with significant changes in mLDFA and MPTA (p < 0.001). In UKAs, 68% of patients demonstrated a postoperative HKA between 171.2° and 175.7°, whereas in TKAs, values clustered between 174.5° and 179.8°. Mann-Whitney U test demonstrated no statistically significant differences between the UKA and TKA cohorts across all assessed PROMs, including OKS, SF-12, and FJS (p > 0.05 in all). 98% of the UKA and 94% of the TKA cohort achieved excellent or good outcomes.
CONCLUSION: UKA performed in carefully selected patients with large varus deformities (> 15°) can provide satisfactory short- to mid-term outcomes. Although no statistically significant differences were observed in postoperative PROMs between the UKA and TKA groups, the current study was not designed or sufficiently powered to establish equivalence or detect subtle clinically meaningful differences between procedures. Greater deformity correction was achieved with TKA; however, UKA also resulted in substantial correction despite persistence of some residual varus in certain patients with severe preoperative deformity. Neither the severity of preoperative deformity nor the degree of postoperative residual varus demonstrated a statistically significant correlation with postoperative outcomes in this cohort.
PMID:42429970 | DOI:10.1007/s00402-026-06403-3
